rs7903146 mutation of Type 2 diabetes mellitus-related gene TCF7L2 is not associated with polycystic ovary syndrome in a cohort of Turkey

SUMMARY OBJECTIVE The aim of this study was to investigate whether TCF7L2 gene mutation rs7903146 is in association with polycystic ovary syndrome (PCOS). METHODS A total of 44 PCOS and 48 control participants were recruited for this study. After DNA extraction from peripheral blood, quantitative PCR method was used for genotyping. With a case-control study design, two groups were compared for genotype and allele frequencies as well as clinical characteristics. RESULTS Mean testosterone level was significantly higher in PCOS group, whereas mean progesterone level was significantly higher in control group. In PCOS group, mean thyroid-stimulating hormone (TSH) level was significantly higher in polymorphic allele carriers. Genotype and allele frequencies were not different between groups. CONCLUSIONS When investigated for the first time in a population from Turkey, no association between PCOS and TCF7L2 gene rs7903146 polymorphism was detected. However, considering contradictory results of other populations and low cohort scale of this study, replication studies with greater cohorts are needed.

Asociación del polimorfismo rs7903146, del gen TCF7L2, con marcadores de adiposidad y metabólicos en población chilena - resultados del estudio GENADIO / Association of the TCF7L2 (RS7903146) genotype with adiposity and metabolic markers in the Chilean adult population

Background: Type 2 diabetes etiology has a strong genetic component. More than 20 genetic variants have been associated with diabetes and other metabolic markers. However, the polymorphism rs7903146 of the TCF7L2 gene has shown the strongest association. Aim: To investigate the association of TCF7L2 (rs7903146) genotype with adiposity and metabolic markers in the Chilean adult population. Material and Methods: The association of TCF7L2 (rs7093146) with adiposity and metabolic markers was studied in 301 participants. The outcomes of the study were adiposity markers (body weight, body mass index (BMI), fat mass and waist circumference) and metabolic markers (blood glucose, insulin, HOMA-IR, lipid profile, high sensitivity C-reactive protein (CRP), alanine aminotransferase (ALT), gamma glutamyl transpeptidase (GGT) and leptin). Results: There was an association between the polymorphism TCF7L2 genotype and fasting blood glucose. The latter increased by 4.86 mg/dl per each copy of the risk allele [(95% confidence intervals (CI): 0.48; 9.24), p = 0.03] in the unadjusted adjusted model. However, this association was slightly attenuated in the fully adjusted model [4.38 mg/dl (95% IC: 0.16; 8.60), p = 0.04)]. There were no associations between the TCF7L2 genotype and any other metabolic or adiposity outcome. Conclusions: These findings confirm the association between the TCF7L2 (rs7903146) and fasting glucose in the Chilean population. However, further studies are needed to confirm the association between the TCF7L2 and diabetes risk in the Chilean population.

Type 2 diabetes-associated genetic variants of FTO, LEPR, PPARg, and TCF7L2 in gestational diabetes in a Brazilian population

ABSTRACT Objective Gestational diabetes mellitus (GDM) is a metabolic disorder that shares pathophysiologic features with type 2 diabetes mellitus. The aim of this study was to investigate the association of the polymorphisms fat mass and obesity-associated (FTO) rs1421085, leptin receptor (LEPR) rs1137100, rs1137101, peroxisome proliferator-activated receptor gamma (PPARg) rs1801282, and transcription factor 7-like 2 (TCF7L2) rs7901695 with GDM. Subjects and methods 252 unrelated Euro-Brazilian pregnant women were classified into two groups according to the 2015 criteria of the American and Brazilian Diabetes Association: healthy pregnant women (n = 125) and pregnant women with GDM (n = 127), matched by age. The polymorphisms were genotyped using fluorescent probes (TaqMan®). Results All groups were in Hardy-Weinberg equilibrium. The genotype and allele frequencies of the studied polymorphisms did not show significant differences between the groups (P > 0.05). In the healthy and GDM groups, the C allele frequencies (95% CI) of the FTO rs1421085 polymorphism were 36.8% [31-43%] and 35.0% [29-41%]; the G allele frequencies (95% CI) of the LEPR rs1137100 polymorphism were 24.8% [19-30%] and 22.8% [18-28%]; the G allele frequencies (95% CI) of the LEPR rs1137101 polymorphism were 43.6% [37-50%] and 42.9% [37-49%]; the G allele frequencies (95% CI) of the PPARg rs1801282 polymorphism were 7.6% [4-11%] and 8.3% [5-12%]; and the C allele frequencies (95% CI) of the TCF7L2 rs7901695 polymorphism were 33.6% [28-39%] and 39.0% [33-45%], respectively. Conclusion The studied polymorphisms were not associated with GDM in a Brazilian population.

Design of an allele-specific PCR assay to genotype the rs12255372 SNP in a pilot study of association between common TCF7L2 polymorphisms and type 2 diabetes in Venezuelans

Objective The global burden of diabetes mellitus will impact strongly American countries in the coming decades. Type 2 diabetes mellitus (T2DM) is a multifactorial disease and the basis for its genetic susceptibility remains not fully understood. Different population studies have demonstrated that variants of the TCF7L2 gene are strongly associated with an increased risk of T2DM. Moreover, institutions or countries with limited budget to conduct genetic research need cost effective methods for detecting DNA variants. Subjects and methods We standardized a rapid and simple allele-specific PCR method for genotyping the rs12255372 single nucleotide polymorphism (SNP) in a pilot study exploring the association of three TCF7L2 polymorphisms (rs7903146, rs12255372 and DG10S478) with T2DM in 70 patients and 73 controls from Venezuela. Results The performance of the designed allele-specific PCR reaction for rs12255372 genotyping was reliable and accurate. Patients carrying the TCF7L2 rs7903146 T allele (CT + TT genotypes) and heterozygous CT genotype had a significantly higher risk for T2DM (OR = 2.9 and 2.3, respectively). Although rs12255372 and DG10S478 risk alleles predominated in T2DM group no statistical significance was found. Conclusions We developed a novel allele-specific PCR method for easier and rapid detection of rs12255372 polymorphism without the use of expensive instrumentation and reagents. Our study in a relatively small sample of the Venezuelan population replicated the association of the rs7903146 SNP with T2DM. Further studies with larger sample size and more biochemical data should be conducted to explore the genetic basis of T2DM susceptibility in Venezuela.